Vacuum-cleaner filter bag for a hand-held vacuum cleaner

ABSTRACT

The invention comprises a vacuum-cleaner filter bag (1) having a bag wall (2) and a retaining plate (3), the retaining plate (3) the retaining plate (3) comprising an least partially cylindrical connection piece (4) extending in the direction of the through opening (5) formed in the retaining plate (3), the bag wall (2) being connected to the lateral surface of the connection piece (4) along the periphery of the connection piece.

The invention relates to a vacuum-cleaner filter bag, in particular avacuum-cleaner filter bag for a hand-held vacuum cleaner and/or aso-called stick vacuum cleaner, in particular for cordless models.

Stick vacuum cleaners are usually, but not always, cordless devices(battery-powered vacuum cleaners) in which an electric brush isconnected to the actual housing of the hand-held vacuum cleaner via asuction tube without a suction hose. These devices are very light andhandy. The sticks have low input power in the range of about 150 to 600W. The volume flows achieved are correspondingly low and are in a rangeof 10 to 30 I/s. The filter housing is typically cylindrical and has asmall volume (about 1 to 2 liters). A cyclone separator is usually usedas the filter. The cyclone separator accelerates the suction air and theparticles contained therein. As a result, a considerable part of theavailable power is consumed and only little power is left for thegeneration of a sufficient volume flow. The cleaning effect (dustcollection) is often unsatisfactory.

A filter bag made of modern nonwoven laminates fulfills the separationof dust in a much more energy-efficient way. However, it is difficult toproduce a filter bag that fits optimally into the very smallinstallation space available and provides sufficient filter surface.

Classic flat bags, in which two filter material pre-cuts are weldedcircumferentially and a retaining plate is connected planarly to one ofthe filter material pre-cuts, are usually unsuitable because theavailable installation space is too small. For this reason, bags with abottom, such as a block bottom, have mainly been used up to now, inwhich the retaining plate is arranged on the bottom and the bag shape isadapted to the installation space (so-called “three-dimensional” bags).However, producing such bags, especially with a nonwoven materialcommonly used today, has proved difficult. As a result, manualmanufacturing steps are still sometimes required in the production ofsuch bags, which reduces manufacturing efficiency.

It is therefore the object of the invention to provide a vacuum-cleanerfilter bag that can be produced simply and automatically, in particulara vacuum-cleaner filter bag for a hand-held vacuum cleaner and/or astick vacuum cleaner, which can use the available installation space asoptimally as possible.

This object is solved by a vacuum-cleaner filter bag according to claim1. Particularly advantageous further embodiments can be found in thedependent claims.

Thus, the invention provides a vacuum-cleaner filter bag comprising abag wall and a retaining plate, the retaining plate comprising an atleast partially cylindrical connection piece extending in the directionof the through-opening formed in the retaining plate, the bag wall beingconnected to the lateral surface of the connection piece along theperiphery of the connection piece.

The fact that the bag wall is connected to the retaining plate via theat least partially cylindrical connection piece and to its outer surfacealong the lateral surface of the connection piece means that thetime-consuming, and otherwise often only manually possible, formation ofa bottom during manufacture can be dispensed with. As a result, thevacuum-cleaner filter bag according to the invention can be manufacturedmore efficiently.

The vacuum-cleaner filter bag can be provided in particular forhand-held vacuum cleaners and/or a so-called stick vacuum cleaner,especially for cordless models. The filling volume can therefore bebetween 0.5 and 3 liters, in particular between 0.5 and 2 liters, whenfully unfolded.

The retaining plate of the vacuum-cleaner filter bag may be attached toa retaining means in a vacuum cleaner housing. This allows the retainingplate to be arranged, in particular fixed, in a predetermined positionin the vacuum cleaner housing.

In contrast to a flat bag, in which the retaining plate is connected toa flat wall part of the bag wall, in the case of the manufacture of thevacuum-cleaner filter bag according to the invention, the bag wall,which is provided with a corresponding opening, is slipped over the atleast partially cylindrical connection piece of the retaining plate andconnected to its lateral surface. As a result, the vacuum-cleaner filterbag extends substantially parallel to the longitudinal axis of theconnection piece and thus in the direction of inflow through thethrough-opening of the retaining plate into the bag. Thus, thevacuum-cleaner filter bag is also better adapted to the usual filterhousings of hand vacuum cleaners and/or stick vacuum cleaners, which aretypically cylindrical in shape, and which have the retaining means forthe retaining plate on one of the top surfaces of the cylinder.

The at least partially cylindrical connection piece thus comprises thethrough-opening of the retaining plate so that an inflow opening isformed via which dust-laden air can flow into the interior of thevacuum-cleaner filter bag during operation. The longitudinal axis of theconnection piece is defined herein as the direction in which thethrough-opening extends in the connection piece. In particular, thisdirection is perpendicular to the plane in which a connecting plate ofthe retaining plate is arranged, which is connectable to a retainingmeans of the vacuum cleaner.

“At least partially cylindrical” means that the connection piececomprises at least one section which is formed in the shape of acylinder, i.e. defined by a lateral surface and two boundary surfaces.The cylindrical shape is not limited to a circular cylinder. Thecross-section of the cylindrical section, i.e., the directrix of thegeneral cylinder, may be of any shape. The cross-section of thecylindrical section may also be a polygon. In this case, one can alsospeak of a prism-shaped section. In particular, the cylindrical sectionmay have the shape of a straight or perpendicular cylinder, with thegeneratrices extending parallel to the longitudinal axis of theconnection piece.

The connection piece may comprise a second section, in particularadjacent to the cylindrical section, with an enlarged circumferencecompared to the cylindrical section. In particular, the second sectionmay project outwardly beyond the lateral surface of the cylindricalsection. This second section may correspond to the connecting plate ofthe retaining plate or be part thereof.

The connecting plate may in particular be a flat component, inparticular with its extension in two directions (length, width) beingsubstantially greater, in particular at least three times greater, thanin a direction perpendicular thereto (thickness). The connecting platemay in particular completely surround the through-opening of theretaining plate. The through-opening of the retaining plate may inparticular extend through the connecting plate and the connection piece.

The retaining plate may comprise or consist of one or a plurality ofplastic materials. In particular, recycled plastics may be used, such asrecycled polypropylene, rPP, and/or recycled polyethylene terephthalate,rPET.

The retaining plate may comprise a closure element for closing theinflow opening. This allows the suction material to be retained insidethe bag, in particular when the bag is removed.

The retaining plate is formed integrally with the connection piece. Theretaining plate and the connection piece are thus a common component.

The retaining plate may be an injection-molded part or a part producedby thermoforming. The retaining plate may also be manufactured partly byinjection molding and partly by thermoforming.

The retaining plate may further comprise a sealing lip surrounding thethrough-opening. The sealing lip may comprise or consist of athermoplastic elastomer, for example based on polypropylene. The sealinglip is intended to prevent or limit the escape of dust from thevacuum-cleaner filter bag by sealing the area between the inner edge ofthe through-opening and the outside of a connecting connection piece ofthe vacuum cleaner.

The bag wall is made of an air-permeable material and can have amultilayer structure. In the latter case, it is also referred to as alaminate. A plurality of layers of the laminate, in particular eachlayer of the laminate, may comprise or consist of a nonwoven fabricand/or a fiber nonwoven.

As the material for the bag wall, in particular for one or a pluralityof layers of nonwoven fabric or fiber nonwoven, a wide variety ofplastics may be used, for example polypropylene and/or polyester. Thebag wall may also comprise or consist of plastic recyclate and/orrecycled material from the manufacture of textiles (TextileLeft-Over—TLO).

Relevant international standards exist for many plastic recyclates. ForPET plastic recyclates, for example, DIN EN 15353:2007 is relevant. PPrecyclates are characterized in DIN EN 15345:2008. For the purpose ofthe corresponding special plastic recyclates, the present patentapplication adopts the definitions of these international standards. Theplastic recyclates may be non-metallized. An example of this is plasticflakes or chips recovered from PET beverage bottles. Likewise, theplastic recyclates may be metallized, for example, if the recyclateswere obtained from metallic plastic films, in particular metallized PETfilms (MPET).

Recycled polyethylene terephthalate (rPET) can be obtained, for example,from beverage bottles, in particular from so-called bottle flakes, i.e.pieces of ground beverage bottles.

The recycled plastics, in particular recycled PET and/or recycled PP, inboth the metallized and non-metallized versions, can be spun into theappropriate fibers from which the corresponding staple fibers ormeltblown or spunbond nonwoven fabrics can be made for the purposes ofthe present invention.

Recycled material from the manufacture of textiles (TLO) is generated inparticular during the processing of textile materials (in particulartextile fibers and filaments, as well as linear, planar and spatialtextile structures produced therewith), such as the manufacture(comprising carding, spinning, cutting and drying) or recycling oftextile materials. These powdery and/or fibrous materials representwaste materials that can deposit on the machines or filter materialsused to process the textiles. The dusts (powders) or fibers are normallydisposed of and thermally recycled.

The recycled powdery and/or fibrous recycled material is therefore, forexample, production waste; this applies in particular to material thatis a waste product produced during carding, spinning, cutting or dryingof textile materials. In this case, one also speaks of “pre-consumerwaste”.

The recycling of textile materials, i.e. the processing (e.g. shredding)of used textile materials or textiles (e.g. old clothes) also producespowdery and/or fibrous recycled material; this is referred to as“post-consumer waste”.

Thus, the recycled material from the manufacture of textiles, TLO, mayinclude, in particular, fibers and or filaments obtained from wastematerials from the textile and clothing industry, post-consumer waste(textiles and the like) and/or products collected for recycling.

For the purposes of the present invention, a nonwoven fabric means arandom mesh that has undergone a solidification step so that it hassufficient strength to be wound or unwound into rolls, for example bymachine (i.e. on an industrial scale). The minimum web tension requiredfor winding is 0.044 N/mm. The web tension should not be higher than 10%to 25% of the minimum maximum tensile force (according to DIN EN29073-3:1992-08) of the material to be wound. This results in a minimummaximum tensile force for a material to be wound of 8.8 N per 5 cm stripwidth.

A fiber nonwoven, or in short “nonwoven” corresponds to a random mesh,which, however, has not undergone a solidification step so that, unlikea nonwoven, such a random mesh does not have sufficient strength to bewound or unwound into rolls by machine, for example.

The term nonwoven fabric (“nonwoven”) is used in other words accordingto the definition given in ISO Standard ISO9092:1988 or CEM StandardEN29092. Details on the use of the definitions and/or processesdescribed herein can also be found in the standard work “Vliesstoffe”(Nonwovens), W. Albrecht, H. Fuchs, W. Kittelmann, Wiley-VCH, 2000.

The nonwoven layers of the bag wall may comprise, in particular, astaple fiber nonwoven and/or an extrusion nonwoven. In particular,filament spunbond nonwovens (also abbreviated to “spunbond nonwoven” or“spunbond”) and/or meltblown nonwovens can be used.

One or a plurality of layers of the bag wall may comprise a cardedmaterial. Both mechanical processes (e.g. needling) and thermalprocesses (e.g. calendering) may be used as the binding step. Alsopossible is the use of binding fibers or adhesives, such as a latexadhesive. Airlaid materials are also possible.

The nonwoven of one or a plurality of layers of the bag wall maycomprise bi-component fibers. Bi-component fibers (BiCo fibers) can beformed from a core as well as a sheath encasing the core. In addition tocore/sheath bi-component fibers, the other common variants ofbi-component fibers, e.g. side-by-side, can also be used.

The bi-component fibers may be present as staple fibers or formed asfilaments in an extrusion nonwoven (for example, meltblown nonwoven).

Correspondingly unsolidified fiber nonwovens are also conceivable, asmentioned.

The nonwoven of one or a plurality of layers of the bag wall may alsohave a micro-creping (Micrex).

The bag wall may also include an odor absorbent.

In particular, the bag wall may include a capacitance layer. Acapacitance layer provides high resistance to impact loading, and allowsfiltration of large dirt particles, filtration of a significant portionof small dust particles, and storage or retention of large quantities ofparticles, while allowing the air to flow through easily, resulting in alow pressure drop at high particle loading.

The bag wall may also include a fine filter layer. A fine filter layeris used to increase the filtration performance of the multilayer filtermaterial by trapping particles that pass through the capacitance layer,for example. To further increase the separation efficiency, the finefilter layer can preferably be electrostatically charged (e.g. by coronadischarge or hydrocharging), in particular to increase the separation offine dust particles.

The fine filter layer may adjoin the capacitance layer, in particulartowards the outside of the bag wall.

A support layer may adjoin the fine filter layer. A support layer(sometimes also called a “reinforcing layer”) is a layer that gives themultilayer composite of the filter material the necessary mechanicalstrength. The support layer may be, in particular, an open, porousnonwoven with a light surface weight. In particular, the support layermay be a spunbonded nonwoven.

However, it is also possible to use a single-layer filter material forthe bag wall. In this case, it may be a meltblown nonwoven inparticular. A suitable material for such a single-layer bag wall isknown, for example, from EP 2 311 360 B1.

In particular, the bag wall may be connected to the outside of theconnection piece, i.e. to the side facing away from the through-openingof the connection piece. This enables advantageous optical control ofthe fastening process during manufacture, in particular visually and/orvia automated image processing.

In particular, the length of the side of the bag wall connected to theconnection piece may correspond to the outer circumference of thecylindrical section of the connection piece. In particular, the bag wallmay be connected to the lateral surface of the connection piece alongthe entire circumference of the connection piece. Both the bag wall andthe lateral surface of the cylindrical section of the connection piecethus fully surround the through-opening of the connection piece.

The bag wall may be bonded or welded to the lateral surface, and/or thebag wall may be clamped between the lateral surface and a clampingelement. The clamping element may in particular be a hollow cylinder. Inthis case, one can also speak of a clamping ring. Fastening by means ofa clamping element alone enables a detachable connection and thusrecycling of the retaining plate and the connection piece.

The retaining plate may be arranged on a short side of the bag wall. Inother words, the longitudinal axis of the vacuum-cleaner filter bag mayextend parallel to the longitudinal axis of the connection piece.

The bag wall may have a surface pleating with at least five pleats. Thesurface pleating of the filter medium has considerable advantages. Dueto the surface pleating, the area through which the flow passes isconsiderably larger than the regular area available for the flow (inflowarea). In other words, the surface pleating allows the bag wall to be atleast partially pleated.

The term pleating is defined in the sense of the present invention as asequence of two or more pleats, a single pleat being defined in thesense of the present invention by two pleat legs and a pleat hinge,respectively.

A surface pleat is a sequence of pleats provided on the bag wall. Such asurface pleat is fixed at most by a part of the seam along a side edge.However, this part of the seam is neither a pleat hinge nor a part ofthe pleat leg of one of the pleats of the pleating.

The vacuum-cleaner filter bag, in particular its bag wall, may furthercomprise at least one side pleat.

A side pleat is a sequence of pleats in the area of the side edge of thevacuum-cleaner filter bag. The seam along the relevant side edge of thevacuum-cleaner filter bag is here a part of one of the pleats formingthe side pleat; for example, the seam in the region of the relevant sideedge is a pleat hinge or the seam lies almost completely in a pleat leg.

The at least five pleats of the surface pleat may extend along thelongitudinal axis of the filter bag. Alternatively, the pleats may alsoextend transversely to the longitudinal axis.

A fixing device may also be provided to prevent at least one of the atleast five pleats from fully unfolding.

The pleats of a bag wall may be at least partially connected to eachother by means of a fixing device. The fixing device may also keeppleats of the bag wall at a predetermined distance from each other.

The fixing device may comprise at least one material strip, inparticular a nonwoven material strip, or consist of at least onematerial strip, in particular at least one nonwoven material strip. Aplurality of material strips may be spaced apart or directly adjacent toeach other.

A plurality of material strips may extend transversely, in particularperpendicularly or at a predetermined angle, to the longitudinaldirection of the pleats. The predetermined angle may be greater than 0°and smaller than 180°, in particular greater than 30° and smaller than150°.

The fixing device is preferably arranged on the upstream side inrelation to the bag wall. Here, on the upstream side means facing theinterior of the vacuum-cleaner filter bag. The fixing device may be atleast partially connected in particular directly in particular bondedand/or welded to the bag wall, in particular to the pleats of the bagwall. Furthermore, the fixing device may be bonded and/or welded atpoints where pleat legs of two different pleats of the bag wall adjoineach other.

The fixing device may be bonded and/or welded to the bag wall in one ora plurality of areas of the bag wall, each of which is arranged betweentwo pleats of the bag wall. Particularly in the case of horizontalpleats that do not overlap one another, this allows simple production ofthe vacuum-cleaner filter bag.

Two or more of the pleats of the bag wall may also be connected togetherby the fixing device, while two or more of the pleats of the bag wallare not connected together by the fixing device.

Alternatively or additionally, the fixing device may be bonded and/orwelded to one or a plurality of pleats of the bag wall in such a waythat the connection loosens during operation of the vacuum-cleanerfilter bag. Thus, the air flow within the vacuum-cleaner filter bag canbe influenced by the at least partially loosening fixing device.

In other words, parts of the fixing device can serve as air distributorsduring operation of the vacuum-cleaner filter bag.

The surface pleats, side pleats and/or fixing devices may be configuredin particular as described in European patent application EP 2 366 319or European patent application EP 2 366 320.

The side of the bag wall opposite the retaining plate may be concave orconvex. This allows better utilization of the installation space.

The invention also provides a method for manufacturing a vacuum-cleanerfilter bag according to claim 10, in particular for manufacturing avacuum-cleaner filter bag described above. Thus, the method according tothe invention comprises the following steps:

-   -   a) forming a tubular bag of a filter material open at one side;    -   b) arranging a retaining plate comprising an at least partially        cylindrical connection piece at the wide end of a conical guide        element so that the connection piece of the retaining plate        rests against the lateral surface of the conical guide element;    -   c) slipping the bag over the conical guide element;    -   d) connecting the bag to the lateral surface of the connection        piece facing away from the guide member; and    -   e) lifting the bag connected to the connection piece from the        guide element.

This method allows efficient and automated production.

Forming the tubular bag open at one side may include overlapping twofilter material webs and forming two longitudinal welding seams and onetransverse welding seam. Alternatively, forming the tubular bag open onone side may comprise flipping over a single filter material web andforming a longitudinal welding seam to join two edges of the web offilter material that overlap after flipping over, and forming atransverse welding seam.

Forming the tubular bag open at one side may further include forming thesurface pleat and/or side pleat described above.

In particular, the surface pleats may be introduced along the conveyingdirection of the filter material web. If the pleats are to run along thelongitudinal direction of the vacuum-cleaner filter bag, the open sideis provided transverse to the conveying direction of the filter materialweb. If the pleats are to run transversely to the longitudinal directionof the vacuum-cleaner filter bag, the open side is provided in theconveying direction of the filter material web.

The conical guide element can be arranged on a worktable, in particulara rotary table. In particular, a plurality of conical guide elements canbe provided, especially along the circumference of the rotary table. Theradius of the conical guide element may decrease away from the surfaceof the worktable in particular.

The conical guide element may be configured so that its diameter can bechanged or adjusted on the surface of the worktable. For example, theconical guide element may be arranged in a through-opening of theworktable and can be moved perpendicular to the surface of theworktable. Alternatively, the conical guide element may be formed from aplurality of radially displaceable elements.

Arranging the retaining plate with the at least partially cylindricalconnection piece at the wide end of a conical guide element may compriseslipping the retaining plate over the conical guide element. The innerdiameter of the at least partially cylindrical connection piece, i.e.the diameter of its aforementioned through-opening, may correspond tothe outer diameter of the conical guide element at the surface of theworktable, so that the connection piece abuts the outer surface of theconical guide element. For this purpose, the conical guide element mayhave a cylindrical portion at its wide end, the shape and extension ofwhich correspond to the shape and extension of the cylindrical portionof the connection piece, but the outer radius of the cylindrical portionof the conical guide element corresponds to the inner diameter of thecylindrical section of the connection piece.

Slipping the bag over the conical guide element may comprise grippingand opening the tubular bag that is open on one side. Slipping the bagover the conical guide element may be performed in particularautomatically by a robot gripper.

In the case of pleats provided transverse to the longitudinal directionof the vacuum-cleaner filter bag, the open side of the bag is providedin the conveying direction of the filter material web. In this case, therobot gripper rotates the bag before it slips it over the conical guideelement.

In the case of pleats provided in the longitudinal direction of thevacuum-cleaner filter bag, the open side of the bag is providedtransverse to the conveying direction of the filter material web. Inthis case, the robot gripper can take over the bag in the conveyingdirection of the filter material web and slip it over the conical guideelement.

The bag may be connected to the outer surface of the connection piecefacing away from the guide element in particular by ultrasonic welding.The conical guide element forms the anvil for the sonotrode. Welding canbe carried out in several steps. For example, a rotary table can be usedto move the conical guide element with the bag slipped over it todifferent welding stations, which are arranged and configured to welddifferent segments of the circumference of the connection piece to thebag wall. Alternatively, a welding sonotrode movable in thecircumferential direction can also be used.

Alternatively or additionally, connecting the bag to the lateral surfaceof the connection piece facing away from the guide member may comprisearranging a clamping member over the bag wall so that the bag wall isclamped between the lateral surface of the connection piece and theclamping member in a region of the lateral surface of the connectionpiece.

The lifting of the bag connected to the connection piece from the guideelement may again be automated via a robot gripper. Lifting the bagconnected to the connection piece from the guide element may alsoinclude reducing the diameter of the conical guide element on thesurface of the worktable, for example by lowering the conical guideelement in a through-opening of the worktable.

The method may further comprise an optical inspection of the connectionbetween the bag wall and the lateral surface according to step d). Inparticular, at least one digital image of the connection area of the bagwall with the lateral surface may be generated. This digital image maybe subjected to automated image processing to detect defects at theconnection, such as insufficiently formed welding seams. Based on thedetection of an insufficient connection, a warning signal can be issuedand/or the bag in question can be outfed.

Further features and advantages of the invention are described belowwith reference to the exemplary Figures.

FIG. 1 shows a cross-section through an exemplary vacuum-cleaner filterbag;

FIG. 2 shows a perspective view of an exemplary retaining plate with anat least partially cylindrical connection piece;

FIG. 3 shows a top view of an exemplary tubular bag open at one side forthe production of a vacuum-cleaner filter bag;

FIG. 4 shows a perspective view of an exemplary conical guide member forthe production of a vacuum-cleaner filter bag; and

FIG. 5 shows an illustration of a manufacturing step in the productionof an exemplary vacuum-cleaner filter bag.

FIG. 1 shows a cross-section through an exemplary vacuum-cleaner filterbag 1 with a bag wall 2 and a retaining plate 3. The retaining plate 3,in particular its flat connecting plate, serves to fix the vacuumcleaner filter bag 1 in a corresponding holder in a housing of a vacuumcleaner.

The bag wall is not directly connected to the flat part of the retainingplate 3, i.e. the connecting plate, as is usual in the prior art, but toan at least partially cylindrical connection piece 4 of the retainingplate 3. In particular, the connection piece extends in the direction ofthe through-opening 5 formed in the retaining plate 3, i.e.perpendicular to the plane in which the connecting plate lies. The bagwall 2 is connected along the circumference of the connection piece 4 toits lateral surface, which also extends in the direction perpendicularto the connecting plate.

FIG. 2 shows a perspective view of an exemplary retaining plate with anat least partially cylindrical connection piece 4. The connection piece4 comprises a cylindrical section. The shape of the cylindrical sectioncan be freely selected and is not limited to the shape of a circularcylinder. The axis of the cylindrical section defines the longitudinalaxis of the connection piece 4. Along this longitudinal axis of thecylindrical section, the through-opening of the retaining plate isprovided. This forms an inflow opening for the suction material into thefilter bag, as can be seen in FIG. 1 .

The exemplary retaining plate 3 of FIG. 2 comprises a second section 8adjoining the cylindrical section and having an enlarged circumferencecompared to the cylindrical section.

In particular, the second section 8 projects radially outwardly beyondthe lateral surface of the cylindrical section. This second section 8may correspond to the connecting plate as shown in FIG. 1 .

In the embodiment of FIG. 1 , the bag wall 2 is welded to the lateralsurface of the cylindrical section of the connection piece 4. Inparticular, the ultrasonic welding seams 6 can be seen. In addition, aclamping ring 7 is shown in this embodiment, which clamps the bag wall 2to the lateral surface of the cylindrical section of the connectionpiece 4. Such a clamping ring 7 can also alone provide the connection ofthe bag wall to the lateral surface.

Not shown here, a sealing lip can further be provided at thethrough-opening 5.

FIG. 3 shows a top view of an exemplary tubular bag open on one side, ascan be used in the manufacture of a vacuum-cleaner filter bag accordingto FIG. 1 . The bag wall 2 of the exemplary bag of FIG. 3 comprises twolongitudinal weld seams 12, 13 and a transverse weld seam 14. At thetransverse side 15, the bag is open, i.e. without a weld seam, in orderto enable a connection there with a connection piece as exemplarilyshown in FIG. 2 .

The transverse weld seam 14 could also be configured with a concave orconvex curvature for better utilization of installation space. A bottom,for example in the form of a block bottom, or a side pleat would also beconceivable in the area of the transverse weld seam 14.

In addition, the bag wall 2 in FIG. 3 comprises a plurality of surfacepleats 16 which extend along the longitudinal weld seams 12, 13. At theopen end 15, the pleats are fixed in position by a fixing device 17.

As stated above, the term pleat in the sense of the present invention isdefined as a sequence of two or a plurality of pleats, a single pleat inthe sense of the present invention being defined by two pleat legs and apleat hinge, respectively.

A pleat hinge is the point of a pleat with the smallest radius ofcurvature. A so-called pleat axis is obtained by the imaginaryconnection of the pleat hinges. The pleat axis is also referred to asthe pleat back. The pleat axis may correspond to the longitudinal axisof a pleat. Areas of a pleat with a radius of curvature greater than theminimum radius of curvature of the pleat are called pleat legs. The arealying between the pleat legs of a pleat is called the pleat core. Thepleat legs of a pleat can therefore also have a curvature in particular.

Pleats can also have inflection points. Inflection points are thosepoints of a pleat, in particular the pleat legs, at which the curvatureof the pleat changes from concave to convex. A line connecting severalinflection points of a pleat is called an inflection line (helix line).

Two adjacent pleats can also share a pleat leg. If a plurality of pleatsare provided in this way, a pleat pack or a pleat band can be realized.

A plurality of pleats can also be arranged in a zigzag pattern.

Pleats may also have legs that run parallel to the bag wall. Such legsmay be located between pleats that protrude from the plane of the bagwall and thus have an upstream opening with respect to the bag wall. Inparticular, the width of the parallel leg may be less than, preferablyless than half of, or most preferably less than a quarter of, the widthof the opening of the pleat protruding from the bag wall.

The pleat legs of the pleats can in particular be smooth. “Smooth” inthis context means that the pleat legs do not have any compactionsand/or structuring, in particular which is intended to stabilize theshape of the pleats.

One or a plurality of pleat legs of one or a plurality of pleats maycomprise one or a plurality of embossed structures, in particularwherein the embossed structures do not serve to stabilize the shape ofthe pleats. In this way, a further increase in the area available forfiltration can be achieved.

In particular, the bag wall 2 may have more than 5, 10, 20, 30, 40 or 50pleats, and in particular folds of these pleats.

The pleats of the bag wall may have a substantially regular spacingbetween them. In other words, the distance between the backs of thepleats of each two adjacent pleats may be substantially constant.

Pleats can be horizontal or vertical. Horizontal pleats are pleats whosepleat legs are arranged essentially parallel to the bag wall 2. Verticalpleats are pleats whose pleat legs enclose an angle greater than 0° andless than 180°, in particular greater than 20° or greater than 45°, withthe bag wall 2.

A vertical pleat is also understood to be a pleat in which a plane inwhich both the pleat axis and the inflection line of the pleat lieencloses an angle greater than 45°, in particular greater than 30°particular greater than 10°, with a flat, horizontal surface on whichthe first and/or second bag wall is arranged. In this case, a horizontalpleat can be understood as a pleat in which the plane encloses with thissurface an angle smaller than 45°, in particular smaller than 30°, inparticular smaller than 10°.

To measure or determine the above angles, the vacuum-cleaner filter bag,in particular the pleated nonwoven material, is arranged on a flat,horizontal surface. For this purpose, the vacuum-cleaner filter bag canalso be cut open and, in particular, arranged on the surface in such away that the upstream side or inner side of the original vacuum-cleanerfilter bag rests on the surface.

Horizontal pleats may be mutually overlapping, non-overlapping and/orpartially overlapping.

For the manufacture of an exemplary vacuum-cleaner filter bag, as shownin FIG. 1 , it is necessary to connect the bag wall 2 to the connectionpiece 4. Although the connection piece 4 is made of plastics and has acertain strength, in the case of a connection by welding it would beadvantageous if an anvil were provided to form an abutment. FIG. 4 showssuch an anvil in the form of a conical guide element 18.

As shown in FIG. 5 , the conical guide element 18 can be arrangedvertically on a worktable. The conical guide element 18 is configured insuch a way that its outer diameter at the wide end corresponds to theinner diameter of the cylindrical section of the connection piece 4. Theretaining plate 3 with connection piece 4 is then slipped over theconical guide element 18 as shown in FIG. 5 . A robot gripper can thengrip a tubular bag open on one side, as shown for example in FIG. 3 ,and likewise slip it over the conical guide element 18. Here, too, theconical shape of the guide element 18 is advantageous. Thereupon, awelding of the bag wall 2 to the lateral surface of the cylindricalsection of the connection piece 4 can take place, and this from theoutside. The latter has the advantage that the welding result can bechecked, for example via image processing.

Finally, the retaining plate 3 and the bag wall 2 connected to it arepulled off the conical guide element 18.

It is understood that features mentioned in the previously describedembodiments are not limited to these particular combinations and arealso possible in any other combinations. Furthermore, it is understoodthat geometries shown in the Figures are only exemplary and are alsopossible in any other embodiments.

1. A vacuum-cleaner filter bag, comprising: a bag wall and a retainingplate, the retaining plate comprising an at least partially cylindricalconnection piece extending in a direction of a through-opening formed inthe retaining plate, and the bag wall being connected to a lateralsurface of the connection piece along a periphery of the connectionpiece.
 2. The vacuum-cleaner filter bag according to claim 1, whereinthe bag wall is bonded or welded to the lateral surface of theconnection piece.
 3. The vacuum-cleaner filter bag according to claim 1,wherein the connection piece and the retaining plate are integrallyformed.
 4. The vacuum-cleaner filter bag according to claim 1, whereinthe retaining plate and the connection piece are arranged on a shortside of the bag wall.
 5. The vacuum-cleaner filter bag according toclaim 1, wherein the bag wall has a surface pleat with at least fivepleats.
 6. The vacuum-cleaner filter bag according to claim 5, whereinthe at least five pleats extend along a longitudinal axis of thevacuum-cleaner filter bag or transverse to the longitudinal axis of thevacuum-cleaner filter bag.
 7. The vacuum-cleaner filter bag according toclaim 5, further comprising a fixing device which prevents at least oneof the at least five pleats from unfolding completely.
 8. Thevacuum-cleaner filter bag according to claim 1, further comprising atleast one side pleat.
 9. The vacuum-cleaner filter bag according toclaim 1, wherein a side of the bag wall opposite the retaining plate isconcave or convex.
 10. A method of producing a vacuum-cleaner filter baghaving a bag wall and a retaining plate, the retaining plate comprisingan at least partially cylindrical connection piece extending in adirection of a through-opening formed in the retaining plate, and thebag wall being connected to a lateral surface of the connection piecealong a periphery of the connection piece, the method comprising thesteps of: a) forming a tubular bag of a filter material open at oneside; b) arranging the retaining plate at a wide end of a conical guideelement so that the connection piece of the retaining plate restsagainst a lateral surface of the conical guide element; c) slipping thetubular bag over the conical guide element; d) connecting the tubularbag to the lateral surface of the connection piece facing away from theconical guide member; and e) lifting the tubular bag connected to theconnection piece from the conical guide element.
 11. The methodaccording to claim 10, wherein the bag wall is bonded or welded to thelateral surface of the connection piece.
 12. The method according toclaim 10, wherein the connection piece and the retaining plate areintegrally formed.
 13. The method according to claim 10, wherein theretaining plate and the connection piece are arranged on a short side ofthe bag wall.
 14. The method according to claim 10, wherein a side ofthe bag wall opposite the retaining plate is concave or convex.
 15. Thevacuum-cleaner filter bag according to claim 1, wherein the bag wall isclamped between the lateral surface of the connection piece and aclamping element.
 16. The vacuum-cleaner filter bag according to claim2, wherein the connection piece and the retaining plate are integrallyformed.
 17. The vacuum-cleaner filter bag according to claim 2, whereinthe retaining plate and the connection piece are arranged on a shortside of the bag wall.
 18. The vacuum-cleaner filter bag according toclaim 4, wherein the bag wall has a surface pleat with at least fivepleats.
 19. The vacuum-cleaner filter bag according to claim 4, furthercomprising at least one side pleat.
 20. The vacuum-cleaner filter bagaccording to claim 4, wherein a side of the bag wall opposite theretaining plate is concave or convex.